Known are thermoplastic vulcanizates (TPV). A TPV is a polymeric composition having a thermoplastic matrix through which a thermoset elastomer is distributed. A “thermoset elastomer” is an elastomer irreversibly solidified or “set” when heated, generally due to an irreversible crosslinking reaction. Common thermoset elastomers include crosslinked ethylene-propylene monomer (EPM) rubber and crosslinked ethylene-propylene-diene monomer (EPDM) rubber.
Commercial TPVs are typically produced by dynamically vulcanizing (that is, crosslinking with a peroxide, phenolic resin or sulfur cure system, while vigorously mixing), an elastomer in a thermoplastic matrix. Examples of TPVs include EPM rubber thermoset in a crystalline polypropylene matrix.
The art recognizes the need for TPV's with improved properties such as greater heat resistance, improved low temperature performance, and improved elongation.